21859906560 has 352 divisors, whose sum is σ = 74706001920. Its totient is φ = 5442404352.

The previous prime is 21859906559. The next prime is 21859906567. The reversal of 21859906560 is 6560995812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21859906567) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15190321 + ... + 15191759.

It is an arithmetic number, because the mean of its divisors is an integer number (212232960).

Almost surely, 2^21859906560 is an apocalyptic number.

21859906560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21859906560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37353000960).

21859906560 is an abundant number, since it is smaller than the sum of its proper divisors (52846095360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21859906560 is a wasteful number, since it uses less digits than its factorization.

21859906560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1533 (or 1515 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 51.

The spelling of 21859906560 in words is "twenty-one billion, eight hundred fifty-nine million, nine hundred six thousand, five hundred sixty".